This is a U.S. original patent application which claims priority on Great Britain patent application No. 0122457/5 filed Sep. 18, 2001.
The invention relates to the field of photographic processing, in particular to drum processors.
Drum processors arc well known apparatus for developing paper photographic prints. In this known apparatus the drum is mounted and rotated so that its bottom edge dips into a tray of processing solution. As the drum rotates the motion thereof lifts up the solution on to its surface. The solution is carried around the periphery of the drum and returned to the tray. The paper to be processed is held against the top of the drum floating on this liquid film. The paper is normally held stationary by a fixed backing sheet.
The longest length of paper that can be accommodated by this type of processing device is governed by the maximum length of the drum surface clear of solution. Longer lengths have to pass further around the drum but it has been found that when they pass through the solution tray they leave the drum surface and get lost. If the lengths of paper are guided through the solution and up the other side of the drum uneven processing can occur. These problems do not occur normally with processing sheets having a maximum length of 12 inches (xcx9c30.5 cm) but the diameter of the drum becomes excessive if a long length needs to be processed.
This invention aims to reduce the diameter of drum type processors. This is especially useful when processing long lengths of paper or other photographic media.
According to the present invention there is provided apparatus for processing photographic media including a rotatable drum housed within an enclosure chamber, the chamber having a first opening and a second opening, means, located at the first opening of the chamber, for applying processing solution to the surface of the drum and means for feeding and withdrawing the photographic media to and from the enclosure chamber and around the periphery of the drum, the sensitised side thereof facing the drum.
The present invention further provides a method of processing photographic material comprising the steps of applying processing solution to the outer surface of a rotating drum to form a film of solution around a substantial part of the periphery thereof, the drum being housed in an enclosure chamber, feeding the media to be processed into the chamber and around the periphery of the drum to lie above the film of solution, the sensitised side of the media being in contact with the film of solution, and withdrawing the media from the chamber.
Preferably the solution is re-circulated around the surface of the drum.
Preferably the solution is fed into the top of the enclosure chamber as this provides gravity assisted wetting.
This invention overcomes the excessive diameter required by known processors. The processing solution is preferably supplied to the top of the drum by pumping it from a drain sump at the bottom. Less solution is required than by prior art processors. The application of solution can be controlled. The solution can be applied to both sides of the material. The processor is self loading and as it is smaller than those known in the prior art it requires less energy to heat and run. There are also less moving parts to the processor.
The processor allows the solutions to be changed very easily to optimise the processing.
It is advantageous to have the solution run around the circumference of the drum.